1. Field of the Invention
The present invention generally relates to computer networking technology and more particularly relates to transmission and reception of data over a home network implemented upon a phone line system in a residential home.
2. Description of the Related Art
The Internet is a rapidly growing communication network of interconnected computers and computer networks around the world. Together, these millions of connected computers form a vast repository of multimedia information that is readily accessible by any of the connected computers from anywhere at any time. Just as there is a critical need for high-speed connections to the information on the Internet, there is a growing need to rapidly move the information between devices within a home. Businesses accomplish this by deploying Local Area Networks (LANs); however, networks are not commonly deployed in the home due to the cost and complexity of installing the new wiring system typically required by the traditional LANs. Nevertheless, there exists a phone line system in nearly every home in the United States. Therefore a great demand for a simple high-speed and cost-effective home network based on the existing phone line system is tremendously growing.
The driving force behind the home network is the growth of on-line households and the growing number of homes with two or more personal computers. It is reported that more than 47 percent of US households are likely to have Internet access devices by 2002, with some 20 percent of this subset owning multiple devices that need to share access to the Internet as well as each other. With the increased focus on computers in education and the boom in Internet connectivity, a large number of personal computers being purchased today are additional personal computers, as opposed to replacement units. Today, it is estimated that over 15 million of the nearly 100 million homes in the United States have two or more personal computers. This number is growing 30 percent annually.
FIG. 1A shows one of the current implementations of a multiple access network over existing wiring structure in a home. It is generally understood that the phone line in a home includes two pairs of wires, traditionally referred to as a primary pair of wires and a secondary pair of wires. Technically, either one of the pairs may be used for the telephone communication. A home network card 100 as shown in FIG. 1A uses one pair of wires 101. A primary transmitter 102 and a primary receiver 104 are both coupled to the pair 101 via a line isolator 106. The primary transmitter 102 ensures that transmit data can be transmitted over the pair of wires 101 while the primary receiver 104 ensures that data can be received from the pair of wires 101. Isolation circuit 106, as the name suggests, isolates the operation of the home network card 100 from the regular phone services on the pair of wires 101 so that the normal telephone communication can be carried out without being disturbed due to the data networking over the phone lines.
Analogous to a telephone set, the home network card 100 does not use the second pair of wires 103 available in most household wiring structures today, which, nevertheless, often causes inconvenience to many users. Generally, it is difficult to identify which pair is in operation with other devices when a home network card is to be coupled to a wall outlet unless an instrument is available or the color of the wires is correctly identified. Many users then would have to go through the trials-and-errors in order to couple the network card correctly with other devices. To solve the problems, some simply use a balun circuit 108 as shown in FIG. 1B to facilitate the use of the second pair. Therefore a device may be connected to either pair for communication with other devices.
The balun circuit 108, however, requires that a home owner installs a balun at the egress point that transitions the telephone lines from the public switched telephone network to the home's entry. This intervention is typically complicated and undesirable. Therefore, there is a great need for an interface in a home network card that requires no additional installation by a home owner in order to use either one of the pairs in the existing home phone line system.